Annexin V, PE, 100tests

STEMCELL Technologies supplies a PE (Phycoerythrin)-conjugated cellular protein reagent intended for the detection of apoptotic cells by flow cytometry. The reagent is a member of the annexin family of proteins, which bind to membrane phospholipids in the presence of calcium and show high affinity for phosphatidylserine (PS), a phospholipid normally located in the inner leaflet of the plasma membrane.

During early-stage cell apoptosis, PS is translocated from the inner to the outer leaflet of the plasma membrane, exposing it to the external environment. Annexin V detects this translocation and serves as a characteristic marker for early cell apoptosis. It is used along with viability dyes such as 7-AAD (7-Aminoactinomycin D) or Propidium Iodide. Because PS translocation occurs before the loss of membrane integrity, cells in early apoptosis stain positive for Annexin V and negative for viability dyes, whereas apoptotic death or necrosis shows positive staining for both Annexin V and the viability dye.

The product is stable when stored undiluted at 2 - 8°C; it should not be frozen and should be protected from prolonged exposure to light. It remains stable until the expiry date (EXP) on the label. The verified application is flow cytometry (FC). For flow cytometry staining, cells are washed with 1 - 2 mL of phosphate-buffered saline (PBS) containing 2% fetal bovine serum (FBS), centrifuged at 300 x g for 5 minutes at room temperature (15 - 25°C), and resuspended at 1 - 10 x 10^6 cells/mL in Annexin V Binding Buffer. A 100 µL aliquot of cell suspension is added to a tube, followed by 5 µL of Annexin V, PE and 5 µL of 7-AAD, then gently vortexed and incubated at room temperature for 15 minutes while protected from light. After an optional wash, 200 µL of Annexin V Binding Buffer is added before analysis. The product is for research use only and is not intended for human or animal diagnostic or therapeutic uses.